Deepening a rift ahead of the largest annual gathering of conservative activists in Washington this week, some of the movement’s top leaders have circulated a private memo urging that conservatism’s founding principles be recast to exclude gay rights groups from the Reagan coalition of economic, defense and social conservatives.

The memo, obtained by The Washington Times, was signed by about two dozen leaders, and was released just as the Conservative Political Action Conference is set to begin its most contentious session in years, riven with divisions over a gay rights Republican group that is helping sponsor the conference and the social conservatives who are trying to keep it out.

The fight, which amounts to a battle for primacy among the three major legs of the movement, threatens to rend the conservative coalition at what should otherwise be a heady time. Riding the wave of tea party enthusiasm, conservatives saw big gains for their champions and for the broader GOP in last year’s elections.

But the memo, written under the moniker Conservatives for Unity, argued that there can be no common ground between gay rights conservative activists and social-issues conservatives, and said it’s time to settle the issue.

“It is not necessary for each group within a political movement to embrace the full agenda of others. But it is necessary for each group within any coherent movement not to stand in diametrical opposition to one or more of its core principles. It is our conviction that the institution of marriage and the family qualify as such principles,” said the conservatives.

Their memo was sent to the board of the American Conservative Union and the American Conservative Union Foundation, which organizes CPAC, the three days of speeches, workshops and social activities that are the high point of conservative activism.

Countering the call for exclusion, Larry L. Eastland, a bishop in the Church of Jesus Christ of Latter-day Saints and an ACU board member, warned in a letter to fellow board members to “not be guilty of ‘casting the first stone’ on others’ sins.”

“Let us not lose sight of our goals by closing the door on individuals who will stand with us on public issues on which we agree, and keep to themselves their differences on issues where it could give ‘aid and comfort’ to our opponents,” he wrote.

He said rather than pre-emptive exclusion, CPAC should wait to see whether groups violate the gathering’s fundamental principles and, if they do, they should not be invited back.

The gay rights group in question is GOProud, which says it represents gay conservatives. Its participation already had chased several major social-issues groups from CPAC, including Concerned Women for America and the Family Research Council.

But Christopher Barron, chairman of GOProud’s board, said the boycott has been “a complete and total unmitigated disaster for the boycotters.”

“These are people who have been treated like clowns for years,” he said. “They’re not relevant, they haven’t been relevant, and it’s a disservice to the conservative movement to pretend that their boycott, their non-participation, is somehow symptomatic of a wider split in the conservative movement.”

As a sponsor of CPAC, GOProud will have a booth in the exhibitors hall, will have members as part of panels and presentations, and is sponsoring an off-site party that Mr. Barron said has become the hottest ticket associated with the conference, particularly with the college-aged activists who make up a large percentage of CPAC attendees. Mr. Barron said those younger conservatives do not object to GOProud’s inclusion.

GOProud was a sponsor of last year’s gathering as well, drawing some criticism. Still, that fight was overshadowed in 2010 by former Rep. Tom Tancredo, Colorado Republican, who charged that CPAC “failed the conservative movement” by allowing supporters of legalization of illegal immigrants to have a platform.

The three branches of the conservative movement — social, defense and economic conservatives — have established a peace that powered them to presidential victories in 1980, 1984, 1988, 2000 and 2004, in addition to dramatic congressional victories in 1994.

At times, one branch or another has appeared to be ascendant — such as after the 2004 elections, when “values voters” were considered the hot group. But some saw the 2010 elections, with the tea party movement bolstering the GOP, as a signal that economic and limited-government conservatives had gained the upper hand.

That has led some to cast the battle over GOProud as a proxy for primacy in the conservative coalition, with GOProud leaders saying the elections showed that Republicans should focus on economic issues and shelve social issues.

Colin A. Hanna, president of Let Freedom Ring and one of the signers of the memo, said the problem with GOProud is that it can’t be squared with the rest of the “big-tent” message conservatives profess.

“The agenda of GOProud is fundamentally incompatible with virtually all social conservatives, so this isn’t diversity, it’s discord,” he said.

He added, though, that the fight itself does not break up the Reagan coalition and that his group is not boycotting.

“I think it’s a time to get this stuff straight. Having said what I said, you’ll notice our organization, Let Freedom Ring, will be at CPAC,” he said. “The purpose of the letter is to focus on CPAC next year and beyond, rather than focus on CPAC this week. That decision’s been made. Let’s get it right next time.”

Among other signers of the memo are conservative icon Phyllis Schalfly, former Ohio Secretary of State Ken Blackwell, Center for Military Readiness President Elaine Donnelly and Media Research Center President L. Brent Bozell.

Notably absent were major social-issues groups such as the American Family Association, the Family Research Council and the Heritage Foundation.

With no clear front-runner for next year’s Republican presidential nomination, CPAC’s straw poll will be an early test of strength among the conservatives who dominate primaries. Many of the GOP’s hopefuls will be speaking, including Sen. John Thune, former Massachusetts Gov. Mitt Romney, former Minnesota Gov. Tim Pawlenty and former House Speaker Newt Gingrich.

Missing is former vice-presidential candidate Sarah Palin, who said she has another commitment. Still, she told CBN this weekend that she didn’t question CPAC’s inclusion of GOProud, saying she is open to groups presenting differing opinions and “the more information that people have, the better.”